BOSTON – They beat Pedro Martinez and Derek Lowe, pitchers with filthy stuff. But Tim Wakefield’s dancing knuckleball is a haunting mystery to the Yankees.

Poised to put the Red Sox in a deep ditch last night in Game 4 of the ALCS at Fenway Park, the Yankees succumbed to Wakefield’s floaters for the second time inside a week and dropped a 3-2 decision in front of 34,599.

The loss evens the best-of-seven series at 2-2. Game 5 is today with David Wells facing Lowe. Wells will be watched carefully since he suffered discomfort in his groin area attempting to get out of the dugout during Saturday’s Game 3 melee. If he can’t go or falters early in a venue where he is 10-10 in his career, Jeff Weaver gets the call.

After Saturday’s Game 3 nastiness, last night tilt was incident-free and was decided by homers from Todd Walker and Trot Nixon off Mike Mussina, who was beaten by Wakefield for the second time in the series.

A half step by the heavy-legged Jason Varitek was the difference between the Red Sox taking a 3-1 lead in the seventh and Mussina keeping it to a one-run deficit.

With the bases loaded and one out, Grady Little used Varitek to hit for Doug Mirabelli, Wakefield’s personal catcher. Varitek hit a one-hopper to Derek Jeter’s right that he scooped and fired to Alfonso Soriano at second. But Soriano’s throw to first was a tad soft and a half-step late and that allowed Kevin Millar to score.

Ruben Sierra’s pinch-hit homer with one out in the ninth cut the Red Sox lead to 3-2 but Scott Williamson fanned David Dellucci and Soriano to post the save.

Mussina, who has absorbed all three of the Yankees’ postseason losses, gave up three runs and six hits in 52/3 innings. The two homers raised Mussina’s ALCS total to five surrendered.

Wakefield exited when he issued Jason Giambi a borderline walk leading off the eighth and was replaced by right-hander Mike Timlin, who retired Bernie Williams on fly to deep center, Jorge Posada on a grounder to first and whiffed Hideki Matsui. Wakefield allowed one run and five hits.

Little tried to get into Jeff Nelson’s head in the eighth when he asked the umpires to check Nelson’s glove and belt buckle. Nelson, who with Karim Garcia, will be charged with assault and battery today for their involvement in Saturday’s bullpen brawl, was found clean but that only stoked the crowd that booed Nelson’s every move. It was also Little’s way of getting back at Joe Torre for checking the top of Timlin’s hat in Game 1.

Nelson responded by feeding the ice-cold Nomar Garciaparra a 6-4-3 double play to end the inning.

Mussina didn’t pitch to a batter with a runner in scoring position through six innings but trailed, 2-1, thanks to solo homers by Walker and Nixon, in the fourth and fifth innings, respectively.